Developing open-domain, intelligent dialog systems that can satisfactorily interact like humans, perform complex tasks and/or answer on a range of topics has been one of the most ambitious and difficult goals in Artificial Intelligence (AI). The study of such systems, called Conversational AI (ConvAI), is at the confluence of Natural language Processing (NLP), Information Retrieval (IR), and Machine Learning (ML), attracting significant research from both academia and industry. The recent developments in Deep Learning (DL) [1]}, [2]} and Reinforcement Learning (RL) [3]}, [4]} have further boosted research in the domain, making it one of the most sought after research topics in AI.
